Movable switch contact arrangement having a contact lever holder with a contact lever

ABSTRACT

A movable switch contact arrangement for a low-voltage circuit breaker has a contact lever holder for holding a plurality of contact levers. The contact lever holder includes a base body and additional bodies attachable thereto, as well as external mounting arms for rotatable mounting to open and close the circuit breaker. Contact lever holders of different widths can be produced by combining the base body with additional bodies of different types in order to adapt the circuit breaker to a desired rated current.

FIELD OF THE INVENTION

The present invention relates to a movable switch contact arrangementfor a low-voltage circuit breaker having contact levers and a contactlever holder, rotatably mounted using lateral mounting arms for openingand closing the switch, which holds a contact lever.

BACKGROUND INFORMATION

A switch contact arrangement of this type is described in German PatentApplication No.35 39 786 1. The mounting arms are components of amounting bracket dimensionally matched with a holding body for thecontact levers. While this is a construction containing only metallicparts, switching contact arrangements, composed of a combination ofmolded plastic parts and metallic parts, are also known. In either case,these switch contact arrangements are dimensioned for a given number ofcontact levers. Therefore, for a series of low voltage circuit breakersincluding a plurality of rated currents, an equal number of differentmovable switch contact arrangements would be required.

SUMMARY OF THE INVENTION

An object of the present invention is to reduce the manufacturing costfor this plurality of switch contact arrangements.

According to the present invention, this object is achieved by the factthat the contact lever holder has a central part made up of a base bodyand at least one additional body attachable thereto, and the mountingarms are attached on both sides of the central part.

Thus two components can be uniformly used for all switch contactarrangements of a series of circuit breakers, e.g., the mounting armsand the base body. Only the additional bodies must be provided accordingto the width of the central body, which depends on the number of contactlevers. A dimensionally appropriate assembly of the central part fromits components can be facilitated by the fact that the base body and theadditional body or bodies have connecting surfaces provided withprojections and matching recesses. Thus the base body and the additionalbody or bodies can be assembled like building blocks prior to beingpermanently attached using connecting bolts.

The base body can have at least two threaded holes on each side, whilethe mounting arms and the additional bodies have through holes forconnecting bolts, flush with the threaded holes. Therefore, theadditional bodies only have to have through holes, which do not requirehigh accuracy. This facilitates manufacturing of the additional bodiesas cost-effective components.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a section of a low-voltage circuit breaker with a movableswitch contact arrangement according to an embodiment of the presentinvention.

FIG. 2 shows a switch contact arrangement viewed from the contactingsides of the contact levers.

FIG. 3 shows a contact lever holder with a central part having only onebase body.

FIG. 4 shows a contact lever holder like that of FIG. 3, with a widercentral part having a base body and two additional bodies of a firsttype.

FIG. 5 shows another exemplary embodiment according to the presentinvention of a contact lever holder, whose central part has one basebody and one additional body of a first type, as well as one of a secondtype.

FIG. 6 shows a contact level holder.

FIG. 7 shows a connecting surface of a base body.

FIG. 8 shows a section VIII—VIII of FIG. 7.

DETAILED DESCRIPTION

A low-voltage circuit breaker 1 schematically shown in FIG. 1 has ahousing 2, on which a switch contact system, an arc quenching chamber 3,and a drive device 4 for actuating the switch contact system aremounted. A stationary switch contact 5, connected to an upper connectingbar 6, is part of the switch contact system. A movable switch contactarrangement 7, which interacts with stationary switch contact 5,includes contact levers 10, which are articulatedly mounted on a contactlever holder 11. Flexible conductors 12 are used to connect contactlevers 10 with a lower connecting bar 13, arranged parallel to upperconnecting bar 6. Both connecting bars 6 and 13 protrude from housing 2at its rear side and are used to connect circuit breaker 1 to a loadcircuit.

A switching shaft 14, connected to contact lever holder 11 via anarticulated coupling gear 15, is part of drive device 4. Circuit breaker1 may have a plurality of switch contact systems of the type shown in aparallel arrangement. All poles can be switched on and off using thesame drive device 4 and switching shaft 14.

Each movable switch contact arrangement 7 may have a plurality ofcontact levers 10, as shown in FIG. 2. Contact levers 10 arearticulatedly attached to contact lever holder 11, in a known mannerusing mounting bolt 16 and prestressed in the direction of stationaryswitch contact 5 using contact springs, which engage with contact levers10 on the rear and are therefore not visible in FIG. 2.

Contact lever holder 11 has two lateral mounting arms 17, on whose lowerends mounting pins 20 are provided. Wall bodies 21 of housing 2 ofcircuit breaker 1 are provided with mounting holes 22 for engagingmounting pins 20.

With given mechanical and electrical properties of the individualcontact levers 10, the rated current of the movable switch contactarrangement 7 shown depends on the number of contact levers 10.Therefore switch contact systems for different rated currents can beproduced using a larger or smaller number of identical contact levers.In the following we shall explain how contact lever holder 11 can beadapted to varying numbers of contact levers 10.

First, FIG. 3 schematically shows a contact lever holder. 25, whichincludes a central part A and mounting arms 18, attached thereto on bothsides. Central part A includes a base body 26. Base body 26 is designedas a standard component, preferably having the smallest dimensionsoccurring in a series of low-voltage circuit breakers. The contact leverholders for sizes with higher rated currents are produced by addingadditional bodies of a given type to standard base body 26. As anexample, FIG. 4 shows a contact lever holder 27, whose central part Bincludes a combination of a base body 26 with additional bodies 28 of afirst type attached on both sides. The width available for mountingcontact levers 10 is thus increased from a dimension B1 in FIG. 3 to adimension B2 in FIG. 4. If a second additional body 30 of a second typeis provided, a central part C that includes base body 26 with anadditional body 28 of the first type and an additional body 30 of thesecond type results in a contact lever holder 29 with a useful width B3.

A contact lever holder 31 according to FIG. 6, containing a central partD that includes of a base body 26 with two additional bodies 30 of thesecond type, has an even larger width B4. Mounting arms 18 are connectedto base body 26 or to the central part including base body 26 withadditional bodies 28 and 30 using connecting bolts 32, which areillustrated in a simplified manner through their central axes in FIGS.3, 4, 5, and 6.

Base body 26 and additional bodies 28 and 30 are provided withconnecting surfaces that facilitate joining with the correct dimensions.First, FIG. 7 shows a connecting surface 33 of base body 26 with twothreaded holes 34 and three pin-like projections 35, arrangedapproximately diagonally. The opposite connecting surface 36 containsdepressions 37 corresponding to projections 35.

Additional bodies 28 and 30 are provided with connecting surfaces 33 and36 of the same type, so that base body 26 and additional bodies 28 and30 can be joined in any desired manner. Additional bodies 28 and 30contain through holes 38, flush with threaded holes 32, which areindicated in FIGS. 3, 4, 5, and 6.

Base body 26 and additional bodies 28 and 30 can be provided with websor ribs 39 (FIG. 7) in order to ensure the desired spacing betweencontact levers 10 (FIG. 2).

What is claimed is:
 1. A movable switch contact arrangement for a low-voltage circuit breaker, comprising: contact levers; and a contact lever holder holding the contact levers, the contact lever holder rotatably mounted for switching on and switching off using lateral mounting arms, the contact lever holder including a central part, the central part having a base body and at least one further body, the at least one further body being formed as a separate part with respect to the base body and being attachable to the base body, the mounting arms being attached to first and second sides of the central part.
 2. The movable switch contact arrangement according to claim 1, wherein the base body and the at least one further body have connecting surfaces which have projections and corresponding recesses.
 3. The movable switch contact arrangement according to claim 1, wherein each of first and second sides of the base body has at least two threaded holes, the mounting arms and the at least one further body have through holes flush with the threaded holes for receiving connecting bolts.
 4. The movable switch contact arrangement according to claim 1, wherein: the base body has a uniform size; the at least one further body is provided according to a width of the central part, the width of the central part depending on the number of the contact levers. 